Logging Source Generator fails to compile due to CS0246 and CS0265 errors if type for generic constraint is in a different namespace #58550

martincostello · 2021-09-02T12:09:45Z

Description

If a containing class for a class used to provide the partial methods for the Logging Source Generator uses as class as a type constraint which is defined in another namespace, the project fails to compile with errors similar to the below.

Repro\Microsoft.Extensions.Logging.Generators\Microsoft.Extensions.Logging.Generators.LoggerMessageGenerator\LoggerMessage.g.cs(6,47): error CS0246: The type or namespace name 'Message' could not be found (are you missing a using directive or an assembly reference?) [Repro.csproj]
Repro\MessagePrinter.cs(6,26): error CS0265: Partial declarations of 'MessagePrinter<T>' have inconsistent constraints for type parameter 'T' [Repro.csproj]

If the type which is used for the type constraint of the class is in the same namespace, then project compiles and runs as expected.

The compilation errors can be worked around by using global using statements, such as:

<ItemGroup>
  <Using Include="Repro.AnotherNamespace" />
</ItemGroup>

Minimal repro

`Repro.csproj`

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
    <OutputType>Exe</OutputType>
    <RootNamespace>Repro</RootNamespace>
    <TargetFramework>net6.0</TargetFramework>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="6.0.0-rc.1.21424.15" />
    <PackageReference Include="Microsoft.Extensions.Logging" Version="6.0.0-rc.1.21424.15" />
    <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="6.0.0-rc.1.21424.15" />
  </ItemGroup>
</Project>

`Program.cs`

using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Repro;

using var serviceProvider = new ServiceCollection()
    .AddLogging(builder => builder.AddConsole())
    .BuildServiceProvider();

var loggerFactory = serviceProvider.GetRequiredService<ILoggerFactory>();
var logger = loggerFactory.CreateLogger<MessagePrinter<Message>>();

var printer = new MessagePrinter<Message>(logger);
printer.Print(new() { Text = "Hello" });

`Message.cs`

namespace Repro.AnotherNamespace
{
    public class Message
    {
        public string? Text { get; set; }
    }
}

`MessagePrinter.cs`

using Microsoft.Extensions.Logging;
using Repro.AnotherNamespace;

namespace Repro
{
    public partial class MessagePrinter<T>
        where T : Message
    {
        private readonly ILogger _logger;

        public MessagePrinter(ILogger<MessagePrinter<T>> logger)
        {
            _logger = logger;
        }

        public void Print(T message)
        {
            Console.WriteLine(message);
            Log.Message(_logger, message.Text);
        }

        internal static partial class Log
        {
            [LoggerMessage(EventId = 1, Level = LogLevel.Information, Message = "The message is {Text}.")]
            internal static partial void Message(ILogger logger, string? text);
        }
    }
}

Expected Output

Repro> dotnet run
Repro.Message
info: Repro.MessagePrinter[1]
      The message is Hello.

Configuration

.NET SDK 6.0.100-rc.1.21424.38
Microsoft.Extensions.Logging 6.0.0-rc.1.21424.15

Regression?

No.

The text was updated successfully, but these errors were encountered:

ghost · 2021-09-02T12:09:49Z

Tagging subscribers to this area: @maryamariyan
See info in area-owners.md if you want to be subscribed.

Issue Details

Description

If a containing class for a class used to provide the partial methods for the Logging Source Generator uses as class as a type constraint which is defined in another namespace, the project fails to compile with errors similar to the below.

Repro\Microsoft.Extensions.Logging.Generators\Microsoft.Extensions.Logging.Generators.LoggerMessageGenerator\LoggerMessage.g.cs(6,47): error CS0246: The type or namespace name 'Message' could not be found (are you missing a using directive or an assembly reference?) [Repro.csproj]
Repro\MessagePrinter.cs(6,26): error CS0265: Partial declarations of 'MessagePrinter<T>' have inconsistent constraints for type parameter 'T' [Repro.csproj]

If the type which is used for the type constraint of the class is in the same namespace, then project compiles and runs as expected.

Minimal repro

`Repro.csproj`

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
    <OutputType>Exe</OutputType>
    <RootNamespace>Repro</RootNamespace>
    <TargetFramework>net6.0</TargetFramework>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="6.0.0-rc.1.21424.15" />
    <PackageReference Include="Microsoft.Extensions.Logging" Version="6.0.0-rc.1.21424.15" />
    <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="6.0.0-rc.1.21424.15" />
  </ItemGroup>
</Project>

`Program.cs`

using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Repro;

using var serviceProvider = new ServiceCollection()
    .AddLogging(builder => builder.AddConsole())
    .BuildServiceProvider();

var loggerFactory = serviceProvider.GetRequiredService<ILoggerFactory>();
var logger = loggerFactory.CreateLogger<MessagePrinter<Message>>();

var printer = new MessagePrinter<Message>(logger);
printer.Print(new() { Text = "Hello" });

`Message.cs`

namespace Repro.AnotherNamespace
{
    public class Message
    {
        public string? Text { get; set; }
    }
}

`MessagePrinter.cs`

using Microsoft.Extensions.Logging;
using Repro.AnotherNamespace;

namespace Repro
{
    public partial class MessagePrinter<T>
        where T : Message
    {
        private readonly ILogger _logger;

        public MessagePrinter(ILogger<MessagePrinter<T>> logger)
        {
            _logger = logger;
        }

        public void Print(T message)
        {
            Console.WriteLine(message);
            Log.Message(_logger, message.Text);
        }

        internal static partial class Log
        {
            [LoggerMessage(EventId = 1, Level = LogLevel.Information, Message = "The message is {Text}.")]
            internal static partial void Message(ILogger logger, string? text);
        }
    }
}

Expected Output

Repro> dotnet run
Repro.Message
info: Repro.MessagePrinter[1]
      The message is Hello.

Configuration

.NET SDK 6.0.100-rc.1.21424.38
Microsoft.Extensions.Logging 6.0.0-rc.1.21424.15

Regression?

No.

Author:	martincostello
Assignees:	-
Labels:	`untriaged`, `area-Extensions-Logging`
Milestone:	-

Tornhoof · 2021-09-03T06:10:10Z

Do you really want to punt that to 7.0? Most, if not all, source gen errors for the JSON source generator were classified as blocking.
My reasoning:
This problem also occurs if MessagePrinter is an abstract base class with constraints, I looked through my code where a class gets the non-generic ILogger interface in the constructor (a cursory glance verifies that these are abstract), i.e. an injected logger is used in a shared base class somewhere and ~25% of those types use some kind of generic constraint. That's a few dozen types as that specific project is using MediatR quite heavily.

Many of the source gen compiler errors are sufficiently obscure that without looking at the g.cs, they are not easy to understand.

Having said that, if you can't fix it for 6.0 you want to make sure that you put that bug fairly prominently into the release notes/documentation including the workaround by @martincostello

martincostello · 2021-09-03T06:23:46Z

For what it's worth, I found this in a library code base converting the logging which was using the nested private Log class pattern to the source generators and hit this on three classes, two of which were abstract.

I went with non-abstract for writing up the repro as it was easier to follow.

N0D4N · 2021-11-12T18:42:14Z

Another workaround is to use full qualified name of class in another namespace, that is being used as constraint, e.g.

// code
public partial class MessagePrinter<T> where T : Repro.AnotherNamespace.Message
{}
// code

dasMulli · 2021-12-08T13:14:52Z

Running into this as well trying to convert lots of my code to use this.. happens in 5 files for my MediatR extensions.

Example:

using MediatR;
using Microsoft.Extensions.Logging;

namespace LoggingGeneratorErrorExample;

internal partial class LoggingNotificationHandlerWrapper<TInner, TNotification> : INotificationHandler<TNotification>
    where TNotification : INotification
    where TInner : INotificationHandler<TNotification>
{
    private readonly ILogger<TInner> logger = null!;

    public Task Handle(TNotification notification, CancellationToken cancellationToken)
        => Task.CompletedTask;

    [LoggerMessage(Level = LogLevel.Debug, Message = "Test Message")]
    private partial void LogNotification();
}

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net6.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
    <EmitCompilerGeneratedFiles>True</EmitCompilerGeneratedFiles>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="MediatR" Version="9.0.0" />
    <PackageReference Include="Microsoft.Extensions.Logging" Version="6.0.0" />
  </ItemGroup>
</Project>

Fails with:

C:\demos\LoggingGeneratorErrorExample\Microsoft.Extensions.Logging.Generators\Microsoft.Extensions.Logging.Generators.LoggerMessageGenerator\LoggerMessage.g.cs(6,98): error CS0246: The type or namespace name 'INotification' could not be found (are you missing a using directive or an assembly reference?) [C:\demos\LoggingGeneratorErrorExample\LoggingGeneratorErrorExample.csproj]
C:\demos\LoggingGeneratorErrorExample\Microsoft.Extensions.Logging.Generators\Microsoft.Extensions.Logging.Generators.LoggerMessageGenerator\LoggerMessage.g.cs(7,20): error CS0246: The type or namespace name 'INotificationHandler<>' could not be found (are you missing a using directive or an assembly reference?) [C:\demos\LoggingGeneratorErrorExample\LoggingGeneratorErrorExample.csproj]
C:\demos\LoggingGeneratorErrorExample\LoggingNotificationHandlerWrapper.cs(6,24): error CS0265: Partial declarations of 'LoggingNotificationHandlerWrapper<TInner, TNotification>' have inconsistent constraints for type parameter 'TInner' [C:\demos\LoggingGeneratorErrorExample\LoggingGeneratorErrorExample.csproj]
C:\demos\LoggingGeneratorErrorExample\LoggingNotificationHandlerWrapper.cs(6,24): error CS0265: Partial declarations of 'LoggingNotificationHandlerWrapper<TInner, TNotification>' have inconsistent constraints for type parameter 'TNotification' [C:\demos\LoggingGeneratorErrorExample\LoggingGeneratorErrorExample.csproj]

Build FAILED.

C:\demos\LoggingGeneratorErrorExample\Microsoft.Extensions.Logging.Generators\Microsoft.Extensions.Logging.Generators.LoggerMessageGenerator\LoggerMessage.g.cs(6,98): error CS0246: The type or namespace name 'INotification' could not be found (are you missing a using directive or an assembly reference?) [C:\demos\LoggingGeneratorErrorExample\LoggingGeneratorErrorExample.csproj]
C:\demos\LoggingGeneratorErrorExample\Microsoft.Extensions.Logging.Generators\Microsoft.Extensions.Logging.Generators.LoggerMessageGenerator\LoggerMessage.g.cs(7,20): error CS0246: The type or namespace name 'INotificationHandler<>' could not be found (are you missing a using directive or an assembly reference?) [C:\demos\LoggingGeneratorErrorExample\LoggingGeneratorErrorExample.csproj]
C:\demos\LoggingGeneratorErrorExample\LoggingNotificationHandlerWrapper.cs(6,24): error CS0265: Partial declarations of 'LoggingNotificationHandlerWrapper<TInner, TNotification>' have inconsistent constraints for type parameter 'TInner' [C:\demos\LoggingGeneratorErrorExample\LoggingGeneratorErrorExample.csproj]  
C:\demos\LoggingGeneratorErrorExample\LoggingNotificationHandlerWrapper.cs(6,24): error CS0265: Partial declarations of 'LoggingNotificationHandlerWrapper<TInner, TNotification>' have inconsistent constraints for type parameter 'TNotification' [C:\demos\LoggingGeneratorErrorExample\LoggingGeneratorErrorExample.csproj]
    0 Warning(s)
    4 Error(s)

Generated code emitted by the generator:

// <auto-generated/>
#nullable enable

namespace LoggingGeneratorErrorExample
{
    partial class LoggingNotificationHandlerWrapper<TInner, TNotification> where TNotification : INotification
    where TInner : INotificationHandler<TNotification>
    {
        [global::System.CodeDom.Compiler.GeneratedCodeAttribute("Microsoft.Extensions.Logging.Generators", "6.0.5.2210")]
        private static readonly global::System.Action<global::Microsoft.Extensions.Logging.ILogger, global::System.Exception?> __LogNotificationCallback =
            global::Microsoft.Extensions.Logging.LoggerMessage.Define(global::Microsoft.Extensions.Logging.LogLevel.Debug, new global::Microsoft.Extensions.Logging.EventId(-1, nameof(LogNotification)), "Test Message", new global::Microsoft.Extensions.Logging.LogDefineOptions() { SkipEnabledCheck = true }); 

        [global::System.CodeDom.Compiler.GeneratedCodeAttribute("Microsoft.Extensions.Logging.Generators", "6.0.5.2210")]
        private partial void LogNotification()
        {
            if (logger.IsEnabled(global::Microsoft.Extensions.Logging.LogLevel.Debug))
            {
                __LogNotificationCallback(logger, null);
            }
        }
    }
}

Tornhoof · 2021-12-08T13:19:44Z

Fwiw, I moved the conversion of my code base to the logger src gen to 7.0. I had way too many build errors for complex examples (mostly this case) that I stopped my attempts.

dasMulli · 2021-12-08T13:35:36Z

I was just hoping this can be fixed sooner not just to get the feature working in non-trivial setups but also b/c the in-box generators are a good source of reference (and documentation.. especially for the newer Roslyn 4 incremental generator APIs) for other people writing generators

Tornhoof · 2021-12-08T13:48:58Z

I was just hoping this can be fixed sooner not just to get the feature working in non-trivial

Yeah I second that, but as there was no feedback from MS when I specifically asked if they want to punt that. There are quite a few logger src gen issues, which either point to missing test coverage, or more likely, that the developer experience is still bad (as the json src gen had similar problems).

maryamariyan · 2021-12-22T07:41:42Z

Yeah I second that, but as there was no feedback from MS when I specifically asked if they want to punt that. There are quite a few logger src gen issues, which either point to missing test coverage, or more likely, that the developer experience is still bad (as the json src gen had similar problems).

Thanks for the feedback. Will take a look and make improvements here.

ericstj · 2022-01-10T18:31:13Z

A couple small observations around possible fixes. I don't think partial files need to restate all the derived types and generic parameter constraints, so it may be possible to just omit things in the generated file. Another approach we've often taken in generated files is to fully qualify all type references, so if we aren't doing that already that might be another thing to consider.

cc @layomia @stephentoub @elinor-fung who've built other generators and may have an opinion here or wish to address a similar bug in other generators.

elinor-fung · 2022-01-11T17:39:31Z

+1 to both @ericstj's suggestions.

For this issue, I think the simplest and correct thing to do would be to just remove the constraints when emitting code for the parent classes and logger class.

runtime/src/libraries/Microsoft.Extensions.Logging.Abstractions/gen/LoggerMessageGenerator.Emitter.cs

Line 81 in b8a8c7a

    
           parentClasses.Add($"partial {parent.Keyword} {parent.Name} {parent.Constraints}");

runtime/src/libraries/Microsoft.Extensions.Logging.Abstractions/gen/LoggerMessageGenerator.Emitter.cs

Line 95 in b8a8c7a

{nestedIndentation}partial {lc.Keyword} {lc.Name} {lc.Constraints}

For the p/invoke generator, we don't have this specific problem with generic constraints (since DllImports can't be in generic types), but in general we try to both avoid unnecessarily re-specifying things on partial class/method definitions and use fully qualified names in the generated code.

- Supports usage of "in" modifier - Improves support for generic constraints Fixes dotnet#58550, dotnet#62644

… / when dealing with constraints (#64593) * Fixes some logging source gen bugs: - Supports usage of "in" modifier - Improves support for generic constraints Fixes #58550, #62644 * Apply PR feedback * Add another test

- Supports usage of "in" modifier - Improves support for generic constraints Fixes #58550, #62644

… / when dealing with constraints (dotnet#64593) * Fixes some logging source gen bugs: - Supports usage of "in" modifier - Improves support for generic constraints Fixes dotnet#58550, dotnet#62644 * Apply PR feedback * Add another test

dotnet-issue-labeler bot added area-Extensions-Logging untriaged New issue has not been triaged by the area owner labels Sep 2, 2021

ghost added this to Untriaged in ML, Extensions, Globalization, etc, POD. Sep 2, 2021

maryamariyan removed the untriaged New issue has not been triaged by the area owner label Sep 2, 2021

maryamariyan added this to the 6.0.0 milestone Sep 2, 2021

ghost moved this from Untriaged to 6.0.0 in ML, Extensions, Globalization, etc, POD. Sep 2, 2021

maryamariyan modified the milestones: 6.0.0, 7.0.0 Sep 2, 2021

ghost moved this from 6.0.0 to Untriaged in ML, Extensions, Globalization, etc, POD. Sep 2, 2021

ghost moved this from Untriaged to 7.0.0 in ML, Extensions, Globalization, etc, POD. Sep 2, 2021

martincostello mentioned this issue Nov 24, 2021

Logger Generator not able to Resolve Generic Type Constraints #62026

Closed

maryamariyan self-assigned this Dec 22, 2021

stephentoub mentioned this issue Jan 11, 2022

Remove constraints from Regex source generator partial class declaration #63637

Merged

This was referenced Jan 19, 2022

Follow up feedback with logging source generator #52549

Closed

Microsoft.Extensions work planned for .NET 7 #64015

Closed

maryamariyan added a commit to maryamariyan/runtime that referenced this issue Feb 1, 2022

Fixes some logging source gen bugs:

be3a808

- Supports usage of "in" modifier - Improves support for generic constraints Fixes dotnet#58550, dotnet#62644

maryamariyan mentioned this issue Feb 1, 2022

Fixes two logging source gen bugs - when using "in" or "ref" modifier / when dealing with constraints #64593

Merged

ghost added the in-pr There is an active PR which will close this issue when it is merged label Feb 1, 2022

maryamariyan closed this as completed in #64593 Feb 2, 2022

ML, Extensions, Globalization, etc, POD. automation moved this from 7.0.0 to Done Feb 2, 2022

ghost removed the in-pr There is an active PR which will close this issue when it is merged label Feb 2, 2022

github-actions bot pushed a commit that referenced this issue Feb 2, 2022

Fixes some logging source gen bugs:

481e0e0

- Supports usage of "in" modifier - Improves support for generic constraints Fixes #58550, #62644

This was referenced Feb 3, 2022

[release/6.0] Fixes two logging source gen bugs - when using "in" or "ref" modifier / when dealing with constraints #64705

Closed

[release/6.0] Fix Logging source generator failures with various syntax #64779

Merged

maryamariyan mentioned this issue Mar 3, 2022

What's new in .NET 7 Preview 2 [WIP] dotnet/core#7107

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Logging Source Generator fails to compile due to CS0246 and CS0265 errors if type for generic constraint is in a different namespace #58550

Logging Source Generator fails to compile due to CS0246 and CS0265 errors if type for generic constraint is in a different namespace #58550

martincostello commented Sep 2, 2021 •

edited

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ghost commented Sep 2, 2021

Description

Minimal repro

`Repro.csproj`

`Program.cs`

`Message.cs`

`MessagePrinter.cs`

Expected Output

Configuration

Regression?

Tornhoof commented Sep 3, 2021 •

edited

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martincostello commented Sep 3, 2021

N0D4N commented Nov 12, 2021

dasMulli commented Dec 8, 2021 •

edited

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Tornhoof commented Dec 8, 2021

dasMulli commented Dec 8, 2021

Tornhoof commented Dec 8, 2021

maryamariyan commented Dec 22, 2021 •

edited

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ericstj commented Jan 10, 2022 •

edited

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elinor-fung commented Jan 11, 2022

Logging Source Generator fails to compile due to CS0246 and CS0265 errors if type for generic constraint is in a different namespace #58550

Logging Source Generator fails to compile due to CS0246 and CS0265 errors if type for generic constraint is in a different namespace #58550

Comments

martincostello commented Sep 2, 2021 • edited Loading

Description

Minimal repro

Repro.csproj

Program.cs

Message.cs

MessagePrinter.cs

Expected Output

Configuration

Regression?

ghost commented Sep 2, 2021

Description

Minimal repro

Repro.csproj

Program.cs

Message.cs

MessagePrinter.cs

Expected Output

Configuration

Regression?

Tornhoof commented Sep 3, 2021 • edited Loading

martincostello commented Sep 3, 2021

N0D4N commented Nov 12, 2021

dasMulli commented Dec 8, 2021 • edited Loading

Tornhoof commented Dec 8, 2021

dasMulli commented Dec 8, 2021

Tornhoof commented Dec 8, 2021

maryamariyan commented Dec 22, 2021 • edited Loading

ericstj commented Jan 10, 2022 • edited Loading

elinor-fung commented Jan 11, 2022

martincostello commented Sep 2, 2021 •

edited

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`Repro.csproj`

`Program.cs`

`Message.cs`

`MessagePrinter.cs`

`Repro.csproj`

`Program.cs`

`Message.cs`

`MessagePrinter.cs`

Tornhoof commented Sep 3, 2021 •

edited

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dasMulli commented Dec 8, 2021 •

edited

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maryamariyan commented Dec 22, 2021 •

edited

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ericstj commented Jan 10, 2022 •

edited

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